1. Technical Field
The present invention relates to a liquid ejecting head unit and a liquid ejecting apparatus, and in particular relates to an ink jet recording head unit and an ink jet recording apparatus which discharges ink as a liquid.
2. Related Art
A liquid ejecting apparatus is an apparatus which is provided with a liquid ejecting head, which is able to eject a liquid as droplets, and ejects various types of liquid from the liquid ejecting head. As a representative of the liquid ejecting apparatus, for example, an image recording apparatus such as an ink jet recording apparatus (printer), which is provided with an ink jet recording head (referred to below as a recording head) and performs recording by ejecting ink in liquid form as ink droplets from a nozzle of a recording head, can be given as an example. In addition, in recent years, without being limited to the image recording apparatus, the liquid ejecting apparatus has been applied also to various types of manufacturing apparatuses such as a display manufacturing apparatus. Then, ink in liquid form is ejected by the recording head of the image recording apparatus, and a solution of various colorants of R (Red), G (Green), and B (Blue) are ejected by a colorant ejecting head in the display manufacturing device. In addition, an electrode material in liquid form is ejected by an electrode material ejecting head in an electrode forming device and a solution of a bioorganic compound is ejected by a bioorganic compound ejecting head in a chip manufacturing device.
In recent years, a configuration has been adopted in the printer described above where one head unit is set as the recording heads (multi-head type), which has a nozzle row formed of a plurality of nozzles which are lined up, being lined up in plurality and fixed to a head fixing member such as a sub carriage. Then, in the configuration where each of the recording heads is screwed into place in a state of having been positioned with regard to the sub carriage, after having been positioned and before screwing, temporary fixing of the recording head is performed using an adhesive agent (for example, instantaneous adhesive agent) with regard to the sub carriage. Due to this, deviation of the position of the recording head due to rotation moment when screwing is prevented when permanently fixing by screwing. In a case where temporary fixing using the adhesive agent in this manner is adopted, it is difficult to remove the recording head which has been fixed once to the sub carriage for repairs or replacement. With regard to a problem such as this, a configuration is proposed where an intermediate member which is referred to as a spacer is interposed between the recording head and the sub carriage (for example, JP-A-2007-90327). According to the configuration, by the spacer being fixed in advance by screwing to the recording head and the spacer and the sub carriage being permanently fixed by screwing after temporary fixing using the adhesive agent between the spacer and the sub carriage, the recording head which is fixed once to the sub carriage is able to be removed from the spacer and the sub carriage by releasing the fastening of the screws between the spacer and the recording head. Due to this, attaching and detaching of the recording head due to replacement or repairing of the recording head is easy.
In a case where the sub carriage is fixed to other parts, external force from the parts is applied to the sub carriage. The sub carriage may be easily deformed when rigidity is low and the position of the recording head with regard to the sub carriage may deviate. In addition, the sub carriage may be deformed when rigidity is low and the initial position of the recording head may deviate not only due to such external forces but also due to creep load or changes in the atmosphere (changes in temperature and humidity and the like). When there is positional deviation of the recording head, the impact accuracy of the ink is reduced. As a result, it is preferable that the sub carriage where the recording head is fixed via the spacer has high rigidity.
Here, this problem exists in the same manner also in ink jet recording heads which are provided with a recording head which is directly fixed to the sub carriage without a spacer. In addition, this problem exists not only in the ink jet recording heads which eject ink droplets but also in the liquid ejecting heads which eject other droplets.